Ultrahigh-Wavenumber Transmitting Element and Near-Field Optical Microscope Using Thereof

Abstract

An ultrahigh-wavenumber transmitting element has at least two anisotropic media having slopes of isofrequency curves complementary with each other. The at least two anisotropic media are layered so as to transmit ultrahigh wavenumber.

1 . An ultrahigh-wavenumber transmitting element, comprising
 at least two anisotropic media having slopes of isofrequency curves complementary with each other, wherein   the at least two anisotropic media are layered so as to transmit ultrahigh wavenumber.   
     
     
         2 . An ultrahigh-wavenumber transmitting element according to  claim 1 , wherein the at least two anisotropic media are layered so as to their optic axis are directed to the same direction. 
     
     
         3 . An ultrahigh-wavenumber transmitting element according to  claim 1 , wherein each of the anisotropic media exhibits anisotropy in permittivity. 
     
     
         4 . An ultrahigh-wavenumber transmitting element according to  claim 1 , comprising a first anisotropic medium exhibiting the isofrequency curve having a hyperbolic form and a second anisotropic medium exhibiting the isofrequency curve having an ellipsoidal form. 
     
     
         5 . An ultrahigh-wavenumber transmitting element according to  claim 4 , wherein the second anisotropic medium exhibiting the isofrequency curve having the ellipsoidal form shows lower loss than the first anisotropic medium exhibiting the isofrequency curve having the hyperbolic form. 
     
     
         6 . An ultrahigh-wavenumber transmitting element according to  claim 1 , satisfying: 
       
         
           
             
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       where N represents a number of layers formed of the anisotropic media and is an integer not less than two; each of θ 1 , θ 2 , . . . , and θ N  represents an angle between a normal of each isofrequency curve formed of an anisotropic medium and an optic axis; each of d 1 , d 2 , . . . , and d N  represents a thickness of each anisotropic medium; λ represents a wavelength of a light beam incident upon the ultrahigh-wavenumber transmitting element. 
     
     
         7 . A near-field optical microscope, comprising:
 a light irradiating part for emitting illumination light toward a sample;   a light receiving part for receiving light;   a microstructure for generating or selectively transmitting near-field light, the microstructure being disposed on at least any one of an emission side of the light irradiating part and an incident side of the light receiving part, and   an ultrahigh-wavenumber transmitting element according to  claim 1 .